Automatically optimizes your pages to minimize the number of network connections and ensure even third party resources won't slow down page rendering.
https://www.cloudflare.com/features-optimizer
Analytics and Tracking · Application Performance
Get access to data on 548,706 websites that are Cloudflare Rocket Loader Customers. We know of 34,695 live websites using Cloudflare Rocket Loader and an additional 514,011 sites that used Cloudflare Rocket Loader historically and 17,106 websites in the United States.
Get a list of 548,706 websites using Cloudflare Rocket Loader which includes location information, hosting data, contact details, 34,695 currently live websites and an additional 16,160 domains that redirect to sites in this list. 514,011 sites that used this technology previously and 17,106 websites in the United States currently using Cloudflare Rocket Loader.